The present invention is directed to an air conveyor for gathering waste film and conveying the film in web form to a convenient disposal unit such as a scrap grinding unit. A principal function of the air conveyor is to gather the film in manageable form for delivery to the scrap grinder.
In a typical manufacturing operation for fabricating heavy plastic film such as 7 to 15 mil Mylar, the plastic is extruded and drawn in web form through the fabricating equipment to windup rolls. During the course of manufacture, large quantities of scrap are generated which must be disposed of. In start-up operations, substandard film is usually formed as the forming equipment is brought to normal operating condition. In addition, during periods of normal manufacturing operation, the film web may break occasionally causing a massive pileup of waste film on the plant floor.
Air conveyors are known for disposing of relatively thin guage film which accumulates during a manufacting mishap. In such air conveyors, the film is moved and conveyed through the action of the conveyor air jets. However, stiffer or heavier film material of from 7 to 15 mils cannot be gathered or converged into convenient form for introduction into a scrap grinder. Heavy film behaves as does sheet metal, plywood, or cardboard in that they fold only in one dimension at a time and are not susceptible to forming compound bends without crinkling or creasing. Because heavy film creases or crinkles, it cannot be handled by an air conveyor of the type disclosed in the copending patent application.
At present therefore, thick scrap film is handled manually. Substandard waste film generated during startup operations is pulled aside and accumulated until normal film forming machine operation is achieved. Then the waste film is disposed of manually. Should the film web rupture during machine operation, the film forming equipment must be shut down while the scrap film is gathered and removed.